EN 60598-2-4(portable luminaires),clause 4.10: for portalbe luminaires with a mass less than 1 kg, a rated current not exceeding 2.5 A and provided with a flexbible cable of length not greater than 2 m,....
EN 60598-2-10(protalbe luminaires for children),clause 10.6.5:the total length of non-detachable flexible cable or cord shall be restricted to 2 m.